chart

Arguments

gain

real vector ( gains (in DB))

phase

real vector (phases (in degree))

flags

a list of at most 4 flags list(sup [,leg [,cm [,cphi]]])

sup

1 indicates superposition on the previous plot 0 no superposition is done

leg

1 indicates that legends are drawn, o: no legends

cm

color index for gain curves

cphi

color index for phase curves

Description

plot the Nichols'chart: iso-gain and iso-phase contour of y/(1+y) in phase/gain plane

chart may be used in cunjunction with black.

The default values for gain and phase are respectively :

[-12 -8 -6 -5 -4 -3 -2 -1.4 -1 -.5 0.25 0.5 0.7 1 1.4 2 2.3 3 4 5 6 8 12]

[-(1:10) , -(20:10:160)]

Examples

s=poly(0,'s')
h=syslin('c',(s^2+2*0.9*10*s+100)/(s^2+2*0.3*10.1*s+102.01))
black(h,0.01,100)
chart(list(1,0,2,3));

clf()
h1=h*syslin('c',(s^2+2*0.1*15.1*s+228.01)/(s^2+2*0.9*15*s+225))
black([h1;h],0.01,100,['h1';'h'])
set(gca(),'data_bounds',[-180 -30;180 30]) //enlarge the frame
chart(list(1,0));

See Also

• nyquist — nyquist plot
• black — Black-Nichols diagram of a linear dynamical system